Method and apparatus for making stonelike units



April 1942- E. M. JENKINS ET AL 2,280,483.

METHOD AND APPARATUS FOR MAKING A STONE-LIKE .UNIT

Filed Feb. 20, 1939 2 She ets-Sheet l ATTORN EY A ril 21, 1942. E. M. JENKINS ETAL 2,280,488

METHOD AND APPARATUS FOR MAKING A STONE-LIKE UNIT Filed Feb. 20, 1939 2 Sheets-Sheet 2 \YJEIEIEIEIEIU TTORNEY Patented Apr. 21, 1942 "OFFME METHOD AND APPARATUS non MAKING STONELIKE UNITS Edward M. Jenkins,.Scarsdale, N. Y., and Ernest Wayne Rembert, Plainfield, N. 5., assignors to Johns-Manville Corporation, New York, N. Y, a corporation of New York Application February 20, 1939, Serial No. 257 402 12 Claims.

The present invention relates to improved facing units, particularly to stone-like units having a mottled or decorative appearance, and to the method of making the same.

At the present time, a material employed in large quantities for the facing of walls, floors, and the like comprises sheets or units formed from a hydraulic cementitious material i'n'hardened condition with reinforcing fibres, preferably asbestos fibres, distributed therethroughout. Heretofore, it has been proposed to provide such sheets or units with a mottled or other decorativesurface appearance. Such proposals have included the application of pyroxylin or oil compositions or the like over a face of the sheet which has been surface colored uniformly or in any desired variegated design. However, such products do not exhibit the desired homogeneity and otherwise fail to provide true simulation of natural stone or the like. The instant invention is particularly concerned with, and has for 1ts principal object, the provision of a stone-like unit of an asbestos-cement composition in which the desired mottled or stone-like appearance results from the composition of the body ofthe unit itself, rather than from surface decoration.

Another object of the'invention is the provision of a unit as referred to above which may have a surface appearance to simulate natural stone, marble, or the like, and which is substantially homogeneous throughout.

Another object of the invention is the provision of a unit of the type referred to which may be in the form of a large relatively thin sheet.

A further object of the invention is the provision of a practical methodof producing the units referred to above.

Briefly stated, the invention is embodied in a sheet unit including a hydraulic cementitious material in hardened condition and reinforcing fibres distributed therethrouehout, alternating portions of the unit being differently colored and integrally united together by means including reinforcing fibres extending across the zones of contact between said portions. The invention also comprises a method of making such unit which includes the formation of an imperfect mixture cf a plurality of differently colored, pastelike, asbestos-cement pigment compositions, strongly compressing and densifying the mixture in a filtering press to cause flow of water therethrough and removal of excess water therefrom, and the hardening of the cementitious material.

Our invention will be more fully understood and further objects andadvantages thereof will become apparent when reference is'made to the more detailed description thereof which is to follow and to the accompanying drawings in Which- Fig. 1 is a perspective view of a unit embodying the instant invention;

Fig. 2 is a diagrammatic side elevational view of an apparatus suitably employed in the practice of the method of the present invention;

Fig. 3 is a view on an enlarged scale of a. portion of the apparatus of Fig. 2;

Fig. 4 is an end elevational view of the apparatus of Fig. 3; and

Fig, 5 is a fragmentary view of an element of the apparatus.

Referring now to the drawings, and particularly to Fig. 1, there is depicted a sheet l0 comprising a suitable asbestos-cement composition and containing alternating portions ll, l2, and I3 of different colors arranged in simulation of natural stone or the like. The portions of different eolor'may extend through or substantially through the sheet and are integrally united by asbestos reinforcing fibres extending individually across the planes of contact between said zones,

cement are preferred examples. In the event that white surface areas are desired, white Portland cement may be employed in part; The fibre reinforcement, which is associated with the cement and distributed approximately uniformly therethroughout, preferably comprises asbestos fibres, such as fibres of chrysotile, crocidolite, amosite, or the like The relatively shortfibered Canadian chrysotile asbestos, as for instance, a fibre that in the standard asbestosscreening test shows about half by weight retained on a 10-mesh screen, has been employed to advantage. The proportion of reinforcing fibres to cementitious material is preferably, say, 15 to 30 parts by weight of the fibres to to70 parts by weight of the cementitious material. The pigmentsemployed to provide the desired variations of color may be any of those conventionally employed in the art, for example, yellow ochre, burnt umber, manganese dioxide, and the like.

In thepreparation of the product disclosed in Fig. 1, anapparatus of the type illustrated diagrammatically in Figs. 2-5, inclusive, is pref-- erably employed. Suitably, the apparatus comprises a dry material mixer 20 of any suitable type, for example, a Day mixeryhaving a rotatable mixing blade or blades 22. The mixer 20 has a valved outlet 24 in communication with a plurality of chutes 26 leading to a plurality of any conventional type, whereby material contained in mixer 28 may be directed through any one of the chutes and into one of the mixers 28. In lieu of the individual valves 30, a single valve, for example, a swing valve operable to close off any two of the chutes, may be employed.

Below the storage mixers 28 are supported a similar number of wet mixers 32, each of which includes rotatable mixing paddles 34 driven in any suitable way, as for'example, by motors 36 individually mountedon each unit, as illustrated. Storage mixers 28 each includes a valved outlet 48 arranged to discharge thecontents of the mixer into a weighing hopper 42 supported over the corresponding wet mixer 32. The weighing hoppers may be of any conventional type, whereby a predetermined quantity of the contents of the storage mixers 28 may be discharged into the wet mixers 32. A water supply line 44 is provided adjacent the wet mixers, the water line including branches 46 opening into the mixers 32. The branches are each suitably provided with a valve 48 and a water measuring device, as for example, a meter 50.

Wet mixers 32 are each provided with a valved 'outlet 52 for discharge of their contents into a hopper 54 supported therebelow. The hopper includes a rotatable or otherwise movable discharge nozzle 56 (see particularly Fig. 4) adapted to be swung from a position remote from the box, as shown in dot and dash lines in Fig. 4, into position to discharge the contents of the hopper into a blending box or tank 58, as shown in full lines in Fig. 4. Although a simple swingable connection has been diagrammatically illustrated for the nozzle 56, it will be understood that any other type of means may be substituted therefor which will permit the discharge of the contents of the hopper into the blending box and removal of the nozzle from the vicinity of the box.

The blending box comprises an open-topped container hingedly supported atGO on a platform 62 adjacent a discharge chute 84. The end of the box adjacent the chute comprises, or has incorporated therein, a gate or valve 66 of suitable construction to permit the substantial complete opening of the end of the box for discharge of the contents thereof down the chute 64. A tilting arrangement is provided for, the box which may comprise, for example, a cable 68 secured to a lower'edge of the box and extending over a pulley Ill and to a drum 12 which may be driven in any suitable manner and under any desired means of control to tilt the box at the desired time in the operation of the apparatus.

Supported above the box is a hydraulic or other lifting device suitably comprising a cylinder [4 and piston '16, the latter being secured to bestos content of the mixes.

a piston rod 18, which, in turn, carries a cross frame 88. The cross frame has extending legs 82, which carry a grid 84. The grid is of substantially the same length and width as the interior of the box and suitably comprises intercrossed steel rods, each of a diameter of, say to /2 inch (see Fig. 5). The walls of the box carry a plurality of abutments 86 (see particularly Figs. 3 and 4) adapted to support a restraining plate 88 of substantially the length and width of the interior of the box, the plate including openings to permit the ready passage of the rods 82 therethrough. Dogs 90 are provided to retain the plate 88 against the abutments 86, the dogs being arranged for advance to and withdrawal from operative position by either manual or automatic means.

In the carrying out of the method of the instant invention, in conjunction with the apparatus described above, a dry mix is first made of asbestos fibre, cement, and a selected pigment if color is desired for the particular mix, in the dry mixer 20 and the same is discharged through a chute 26 into any one or more of the storage mixers 28. A similar dry mix is then made in the mixer 28 including a pigment of another color and similarly discharged into another one or more of the storage mixers 28, this operation being repeated until each of said storage mixers- 15 to parts by weight of asbestos fibre to 85 to '70 parts by weight of hydraulic cement. The proportion of the coloring pigment may be suitably determined to provide the desired intensity of color in the finished'product. The material in each of the storage mixers 28 is then discharged through valve into measuring device 42, from whence it is discharged in a measured quantity into wet mixer 32. The relative amounts of the different colored mixes discharged into the severalwet mixers will depend upon the desired relative predominance of the colors in the product. Thus, for example, a comparatively large quantity of the mix which includes the bazk'ground color for'the product will be measured ou Water in material in the wet mixers 32. The proportion of water added should be largely in excess of the amount required to hydrate the cement and preferably is such that when the compositions are compressed in a filter press, an excess of water will flow throughout the compressed composition and therefrom. At the same time, the proportion of water must not be so great that undesired diffusion of the pigments takes place during the blending operation, later described, or that the composition loses its desired paste-like consistency. The proportion of water required to secure the above conditions will vary with the as- Thus, the asbestos, in addition to serving as a reinforcement in the product, allows a greater proportion of water to be employed than would otherwise be permitted. This is due to the high water retention property of the fibres. -However, it has been determined that for the preferred mix, employing from 15 to 30 parts asbestos fibre and 85 to parts cement, there should be used say, 61 to 77 parts of water.

The operation of the mixers 32 is continued until a homogeneous mixture is obtained and the batches in the mixers are then discharged measured quantities is added to the successively through the hopper 54 into the blending box 58. Prior to the discharge into the blending box, the hydraulic lift is manipulated to place the grid 84 at the bottom of the box, the plate 88 being held above the box and adjacent the frame -'80 (see the full line position of the plate in Fig. 3) by any suitable means, for exleveled, as by means of a rake or the like, before the next batch is dumped thereon. Any suitable number of the layers may beprovided, depending upon the number of different colors desired and the number of mixers employed. It

will be understood that although but three mixers have been shown, any number may be used. After the several layers of the wet asbestoscement-pigment composition are in the box 58, the nozzle 56 is swung from the full line position of Fig. 4 to the dot and dash line position and the plate 88 is lowered to the position shown in Fig. 4 and secured on abutments 86 by dogs 90. The hydraulic lift is then operated to draw the grid upwardly through the several layers, the plate'88 preventing the lifting of the material as a mass. The grid 84 may be drawn through the'material only once or may be raised and lowered one or more complete cycles, depending upon the pattern desired in the completed product. Thus, the more nearly -the mixing approaches completion, the finer will be the pattern. Different .patterns may also be obtained by employing grids having different spacings between the bars, or varying arrangement of the bars, or both. In any event, it will be understood that the mixing is imperfect in order to provide a distinct pattern in the product.

When the mixing has proceeded to the desired extent, the dogs 90 are retracted and grid 84 lifted from the box by the hydraulic lift, the grid picking up the plate 88 and also removing it from the box. Thereafter, the box is tilted by the means 68, 18, and 12 (seeFig. 3), the gate 66 opened, and the contents of the box discharged down the chute 64 .to the bed of a filter press of any suitable or conventional construction (not shown). In the event that the resultant product, as shown in Fig. 1, is to include a uniform color base layer, a standard asbestos-cement mix is first laid in the filtering press and lightly conthe mixers are discharged. In this method, relatively thick sections of the batches are si-. multaneously extruded from each of the extruders and 'cut off to fcrm blocks which fall into a box from which they'are. dumped into the press without further mixing or blending.

Any suitable or conventional finishing steps may be applied to the hardened sheet. Thus, for example, the surface of the sheet may be polished and also lacquer, wax, or other finishing materials may be applied thereto.

The finished product resulting from the abovedescribed method is substantially homogeneous throughout, the several differently colored compositions being integrated with one another. This integrality of structure is due,.for the most part, to the presence of the asbestos fibres which, during the pressing operation and the -flow of water through the material, are extended across the interfaces between the several compositions.

The fibres, in addition to reinforcing the several compositions and extending across the interfaces therebetween, serve the additional function, due totheir natural high water retention properties, of retaining water within the material in the press for a suflicient length of time to permit some flow and displacement of adjacent compositions with equalization of densities and a softness of transition of color from a portion of one color to another in the finished product. can be employed due to the use of the fibres permits of softer consistencies of the compositions resulting in a well-knit structure without ob- ,jectionable color blending.

' erations, while at the same time being plastic and easily deformable, makes possible ready control of the fineness of the color configuration in I the mottled product, due to the relative stability press. The compressed and densified materialis then removed fromthe press and allowed to stand until the cement has hardened.

As an alternative to the method of blending the several batches in the blending box dewet mixers 32 and into which the contents of of the individual color groups. This, furthermore, provides a ready means of controlling the degree of intermingling of the colors at the color boundaries, softer consistencies giving softer transition lines, and harder consistencies giving sharper transition lines, with accompanying sharp configuration. Also, the several differently colored compositions may be of different consistencies, whereby streaks or vein-like intrusions are formed similar to those of a natural stone, such as marble.

Having thus described our invention in rather full detail, it will be understood that these details need not be strictly adhered to, but that various changes and modifications will suggest themselves to one skilled in the art, all falling within the scope Of the invention as defined by the subjoinedclaims.

What we claim is:

' 1. The method of making a stone-like unit of mottled appearance comprising forming a plurality of paste-like, similar but differently colored, substantially homogeneous compositions each including a hydraulic cementitious material and reinforcing fibres distributed therethroughout, mixing the compositions imperfectly and subjecting said mixture to strong compression and densification in a filtering mold to cause water to flow in substantialvolume throughout said mixture and finally therefrom whereby said .compositions are welded into a substantially homogeneous body, and then hardening the cementitious material.

Also, the higher proportion of water that 2. The method of making a stone-like unit comprising forming-a batch comprising a plurality of layers of differently colored, paste-like, substantially homogeneous compositions, each including Portland cement, asbestos fibres, and

water, mixing the batch imperfectly to form alternating differently colored surface portions,

subjecting the batch to strong compression and.

densification in a filtering mold to cause water to fiow throughout the said batch and finally therefrom whereby the colors are blended at the zones of-contact between Said compositions and said compositions are welded into a substantially homogeneous body, and then hardening the cementitious material.

3. The method of making a mottled stone-like unit comprising forming a plurality of paste-like, differently colored, substantially homogeneous compositions, each including a hydraulic cementitious material and refnforcing fibres distributed therethroughout, discharging each of said compositions to form a separate layer in a blending device, imperfectly mixing said compositions in said blending device, discharging said imperfectly mixed compositionsinto a filtering mold, subjecting the compositions to strong compression and densification in said filtering mold, and thereafter hardening the cementitious material.

4. The method of making a mottled stone-like unit comprising forming a plurality of paste-like, differently colored, compositions, each including by weight from 70 to 85 parts of hydraulic cementitious material, from 30 to parts of asbestos fibres, and from 77 to 61 parts of water, with said fibres distributed throughout said compositions, mixing the compositions imperfectly and subjecting said mixture to strong compression and densification in a filter mold to cause water to flow in substantial volume through said mixture and finally therefrom, whereby said compositions are welded into a substantially homogeneous body, and then hardening the cementitious material.

5. The method of making a mottled stone-like unit comprising forming a plurality of paste-like, differently colored, substantially homogeneous substantially homogeneouscompositions, each including by weight from 70 to 85 parts of hydraulic cementitious material, from 30 to 15 parts of asbestos fibres, and from '77 to 61 parts of water, with said fibres distributed throughout said compositions, discharging ralityof dry batches of hydraulic cementitious material, reinforcing fibres and pigment, discharging said batches in measured quantities into separate mixers, mixing said batches with measured quantities of water until each batch is substantially homogeneous, discharging the resultant wet batches successively into a blending device to form superposed layers of the batches therein, imperfectly mixing said layers, discharging the resultant imperfectly mixed com-' position into a filtering mold, subjecting the composition to strong compression and densification in the filtering mold, and thereafter hardening the cementitious material.

7. The method of making a stone-like unit of mottled appearance comprising forming a plurality of dry batches of hydraulic cementitious material, reinforcing fibres and pigment, discharging said batches in measured quantities into separate mixers, mixing said batches with measured quantities of water until each batch is substantially homogeneous, discharging theiresultant wet batches successively into a blending device to form superposed layers of the batches therein, drawing a reticulated member through said superposed layers to imperfectly mix the same, discharging the resultant imperfectly mixed composition into a filtering mold, subjecting the composition to stron compression and densification in the filtering mold. and thereafter hardening the cementitious material.

8. The method of making a stone-like unit of mottled appearance comprising forming a plurality of dry batches of hydraulic cementitious material, reinforcing fibres and pigment, mixing said batches with measured quantities of water until each batch is substantially homogeneous, discharging the resultant wet batches successively into'a blending device to form superposed layers of the batches therein, drawing a reticulated member through said superposed layers while restraining the same from movement fromsaid blending device, to imperfectly mix the same, discharging the resultant imperfectly mixed composition into a filtering mold, subjecting the composition to strong compression and densification in the filtering mold, and thereafter hardening the cementitious material.

9. The method of making a stone-like unit of mottled appearance comprising forming a plurality of dry batches each including by Weight from 70 to 85 parts of hydraulic cementitious material and from 30 to 15 parts of reinforcing fibres, discharging said batches in measured quantities into separate mixers, mixing said measured batches with 77 to 61 parts of water for 100 parts by weight of the measured batch, discharging the resultant wet batches successively'into a blending device to form superposed layers of the batches therein, imperfectly mixing said layers, discharging the resultant imperfectly mixed composition into a filtering mold, subjecting the composition to strong compression and densification in the filtering mold, and thereafter hardening the cementitious material.

10. The method of making a stone-like unit of mottled appearance comprising forming a plurality of dry batches each including by weight from to parts of hydraulic cementitious material and from 30 to 15 parts of reinforcing fibers, discharging said batches in -measu1ed quantities into separate mixers, mixing said meas ured batches with 7'7 to 61 parts of water for parts by weight of the measured batch, discharging the resultant wet batches successively into a blending device to form superposed layers of the batches therein, drawing areticulated member through said superposed layers to imperfectly mix the same, discharging the resultant imperfectly mixed composition into a filtering mold, subjecting the composition to strong compression and densification in thefiltering mold, and thereafter hardening the cementitious material.

11. An apparatus for the manufacture of mottled stone-like units comprising means for forming a plurality of wet batches of hydraulic cementitious material and reinforcing fibres, means for receiving said batches in superposed layers, a

reticulated member disposed for movement through said superposed layers for imperfectly mixing the same, and means for moving said reticulated member.

12. An apparatus for the manufacture of mottled stone-like units comprising means for iorm-. 5

ing a plurality of wet batches of hydraulic cementitious material and reinforcing fibres, means for receiving said batches in substantially parallel, contiguous, superposed layers 'to form a laminated mass, a, reticulated member disposed EDWARD M. JENKINS. ERNEST WAYNE REMBERT. 

